Systems and Cognitive Neuroscience Group, SILS Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
Institute of Basic Medical Sciences, University of Oslo, NO-0316 Oslo, Norway.
Cereb Cortex. 2024 Jan 31;34(2). doi: 10.1093/cercor/bhae002.
Neural circuits support behavioral adaptations by integrating sensory and motor information with reward and error-driven learning signals, but it remains poorly understood how these signals are distributed across different levels of the corticohippocampal hierarchy. We trained rats on a multisensory object-recognition task and compared visual and tactile responses of simultaneously recorded neuronal ensembles in somatosensory cortex, secondary visual cortex, perirhinal cortex, and hippocampus. The sensory regions primarily represented unisensory information, whereas hippocampus was modulated by both vision and touch. Surprisingly, the sensory cortices and the hippocampus coded object-specific information, whereas the perirhinal cortex did not. Instead, perirhinal cortical neurons signaled trial outcome upon reward-based feedback. A majority of outcome-related perirhinal cells responded to a negative outcome (reward omission), whereas a minority of other cells coded positive outcome (reward delivery). Our results highlight a distributed neural coding of multisensory variables in the cortico-hippocampal hierarchy. Notably, the perirhinal cortex emerges as a crucial region for conveying motivational outcomes, whereas distinct functions related to object identity are observed in the sensory cortices and hippocampus.
神经回路通过整合感觉和运动信息以及奖励和错误驱动的学习信号来支持行为适应，但人们对这些信号如何在皮质海马层次结构的不同层次上分布仍知之甚少。我们在一项多感觉物体识别任务中对大鼠进行训练，并比较了同时记录的感觉皮层、次级视觉皮层、旁海马皮层和海马体中神经元集合的视觉和触觉反应。感觉区域主要代表单感觉信息，而海马体则同时受到视觉和触觉的调节。令人惊讶的是，感觉皮层和海马体编码了特定于物体的信息，而旁海马皮层则没有。相反，旁海马皮层神经元在基于奖励的反馈时对试验结果进行信号传递。大多数与结果相关的旁海马细胞对负结果（奖励缺失）做出反应，而少数其他细胞则对正结果（奖励传递）做出反应。我们的研究结果突出了皮质海马层次结构中多感觉变量的分布式神经编码。值得注意的是，旁海马皮层作为传递动机结果的关键区域出现，而与物体身份相关的不同功能则在感觉皮层和海马体中观察到。
